I have a '91 Corvette with the 700r4 transmission. It currently has 60k miles on it. Anyway the transmission has been working fine until the last few weeks it occasionally seemed to slip (the rpms would go up and for 200-300 rpms it would be almost like its in neutral. Ok, no big problem until a few days ago on the highway if i punched it over half throttle the rpms would go up to 5000 and the car would be decelerating because it was like it was in neutral again. This time it lasted much longer (usually about 5 seconds) and for many more rpms. What could be the problem?? TIA.

 

I forgot to mention that the problem only occurs in Drive or Overdrive...if I have the transmission in 2 or 1 it drives fine. Come on I know someone here can help out!

 

Sounds like the 3-4 clutches are smoked. There is only one way to fix that, and that is to have it pulled out and gone through.